Circuit compile and proving key gen enhancements

[jimthematrix]

• allow multiple circuits to be specified: -c anon -c anon_nullifier
• allow compile only without generating the proving keys
• update the js library to require CIRCUITS_ROOT rather than always assuming the circuit WASM to be in the local lib folder

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 63.75%. Comparing base (a7b9e39) to head (1f80f1f).
Report is 11 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #36      +/-   ##
==========================================
+ Coverage   58.58%   63.75%   +5.17%     
==========================================
  Files          18       12       -6     
  Lines         606      538      -68     
==========================================
- Hits          355      343      -12     
+ Misses        209      152      -57     
- Partials       42       43       +1     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[Chengxuan]

As the pkg folder now only contains interfaces and simple wrapper code, it does seem if we have tests in this folder, they'll mostly be boiler plate code.

As long as we can ensure other contributors know this convention, we should be fine.

[Chengxuan]

Pushed a commit with some changes for first time users: 1f80f1f